Open Access
Gizarte digitalerako hezkuntza: adimen artifizialaren eta big dataren erabilerarantz
(Mondragon Unibertsitatea, 2020) Astigarraga, Eugenio; Zubizarreta Pagaldai, Ane; Díaz, Koldo; Ipiña, Nagore; Moreno, Aitor; Galíndez Nafarrate, Edurne; García Blázquez, Itziar; SantaCruz, Sirats; Torres Lete, Maialen; Zuberogoitia, Aitor; Iribas Pardo, Haritz; Gostin, Andrés; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Gizartean izan den iraultza teknologikorik eraldakorrenaren testigu gara; une oro aldatzen eta berreraikitzen den gizarte baten iraultza ezplanifikatuaren testigu. Espazioa globalizatuz eta deslokalizatuz doa; halatan, mikroistorio, mikrokultura eta mikrosegundoen aroa sortu da, mikrolanetarako eta gig-ekonomiarako sarbidea emango diguna. Eredu berri horretan, mezu hipermediatiko eta hipertestualak eraikitzeko kultura nagusitu da, zeinak sortzez jada digitalak baitira. Baina ez hori bakarrik: gure pentsamenduan ere (er)aldaketa gertatu da, eta pentsamendu bisual eta pentsamendu konputazional baten aurrean kokatzen da gizartea.
Open Access
Enhanced tolerance to pulse extinction ratio in Brillouin optical time domain analysis sensors by dithering of the optical source
(SPIE, 2015) Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Sagüés García, Mikel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We demonstrate the relaxation of the stringent requirements placed on the pulse extinction ratio in long-range Brillouin optical time-domain analysis sensors (BOTDA) by modulating the wavelength of the laser source that is used to generate both pump and probe waves. This modulation makes the counter-propagating pulse pedestal and probe waves to become correlated only at certain locations in the fiber, thus reducing the gain experienced by the probe wave, which is precisely the process that limits the performance in long-range BOTDAs. Proof-of-concept experimental results in a 20-km sensing link demonstrate a 6-dB reduction of the required modulator extinction ratio.
Open Access
Pulse coding linearization for Brillouin optical time-domain analysis sensors
(Optical Society of America, 2018) Mariñelarena Ollacarizqueta, Jon; Iribas Pardo, Haritz; Loayssa Lara, Alayn; Institute of Smart Cities - ISC
We introduce a simple method to extend the performance of pulse coding techniques in their application to Brillouin optical time-domain analysis sensors (BOTDA). It is based on applying a simple logarithmic processing on the detected probe wave that compensates the deviation from linearity of the sensor response for long code lengths. The technique ensures that the accumulated effect of a sequence of pulses is equal to the linear addition of the effects of the individual components, which is the essential condition to ensure a correct decoding of the probe gain measurement. We experimentally demonstrate the compensation of the Brillouin frequency shift error induced by the accumulated gain nonlinearity. Furthermore, a proof-of-concept 80 km sensing link within a total 200 km fiber loop demonstrated a better than 2 MHz precision with 2 m spatial resolution.
Open Access
Unibertsitateko irakaslegaiek Lehen Hezkuntzako ikasleentzat Txikipedian sortutako matematikako edukien egokitasuna neurtzen
(Udako Euskal Unibertsitatea, UEU, 2022-12-02) Iribas Pardo, Haritz; Errazkin Vicente, Aitor; Torrealday Gallarreta, Amaia; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Artikulu honek baliozkotze-prozesu bat biltzen du, zeinak egiaztatu nahi izan duen Lehen Hezkuntzako ikasleek matematikako edukiak ulertzeko Txikipedia lagungarri izan duten ala ez, bai testuari zein testuaren osagarri diren ikus-entzunezkoei erreparatuta. Txikipediako matematikako edukiak Mondragon Unibertsitateko Lehen Hezkuntza Graduan irakasle izateko ikasketak egiten ari diren ikasleek sortu dituzte eta Euskal Herriko sei ikastetxetan baliozkotu dira. Emaitzek erakutsi dute Txikipediako sarrerak irakurtzea lagungarria dela ikasleentzat, nahiz eta ikusentzunezkoen ekarpenarekin lotutako emaitzek galdera berriak sorrarazi dituzten. Hala ere, esan dezakegu humanitate digitalek lagun dezaketela matematikaren irakaskuntza hobetzen, bai irakaslegaien formakuntzan zein ikasleen edukien ulermenean ere.
Open Access
Cost-effective Brillouin optical time-domain analysis sensor using a single optical source and passive optical filtering
(Hindawi Publishing Corporation, 2016) Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Mariñelarena Ollacarizqueta, Jon; Sagüés García, Mikel; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We present a simplified configuration for distributed Brillouin optical time-domain analysis sensors that aims to reduce the cost of the sensor by reducing the number of components required for the generation of the two optical waves involved in the sensing process. Te technique is based on obtaining the pump and probe waves by passive optical filtering of the spectral components generated in a single optical source that is driven by a pulsed RF signal. Te optical source is a compact laser with integrated electroabsorption modulator and the optical filters are based on fiber Bragg gratings. Proof-of-concept experiments demonstrate 1m spatial resolution over a 20km sensing fiber with a 0.9MHz precision in the measurement of the Brillouin frequency shiſt, a performance similar to that of much more complex setups. Furthermore, we discuss the factors limiting the sensor performance, which are basically related to residual spectral components in the filtering process.
Open Access
Effects of pump pulse extinction ratio in Brillouin optical time-domain analysis sensors
(Optical Society of America, 2017) Iribas Pardo, Haritz; Mariñelarena Ollacarizqueta, Jon; Feng, Cheng; Urricelqui Polvorinos, Javier; Schneider, Thomas; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
We report on two previously unknown non-local effects that have been found to impair Brillouin optical time-domain analysis (BOTDA) sensors that deploy limited extinction ratio (ER) pump pulses. The first one originates in the increased depletion of the pedestal of the pump pulses by the amplified probe wave, which in turn entails a reduced amplification of the probe and a measurement distortion. The second effect is due to the interplay between the transient response of the erbium-doped fiber amplifiers (EDFA) that are normally deployed to amplify the pump and the pedestal of the pump pulses. The EDFA amplification modifies the pedestal that follows the pulses in such a way that it also leads to a distortion of the measured gain spectra after normalization. Both effects are shown to lead to non-local effects in the measurements that have similar characteristics to those induced by pump pulse depletion. In fact, the total depletion factor for calculations of the Brillouin frequency shift (BFS) error in BOTDA sensors is shown to be the addition of the depletion factors linked to the pump pulse as well as the pedestal. A theoretical model is developed to analyze both effects by numerical simulation. Furthermore, the effects are investigated experimentally in long-range BOTDA sensors. The pedestal depletion effect is shown to severely constrain the probe power as well as the minimum ER of the pulses that can be deployed in BOTDA sensors. For instance, it is shown that, in a long-range dual-probe BOTDA, an ER higher that 32-dB, which is above that provided by standard electro-optic modulators (EOM), is necessary to be able to deploy a probe power of -3 dBm, which is the theoretical limit for that type of sensors. Even more severe can be the limitation due to the depletion effect induced by the EDFA transient response. It is found that the impairments brought by this effect are independent of the probe power, hence setting an ultimate limit for the BOTDA sensor performance. Experimentally, a long-range BOTDA deploying a 26-dB ER EOM and a conventional EDFA is shown to exhibit a BFS error higher than 1 MHz even for very small probe power.
Open Access
Second-order non-local effects mitigation in BOTDA sensors by tracking the BFS profile
(SPIE, 2017) Mompó Roselló, Juan José; Iribas Pardo, Haritz; Urricelqui Polvorinos, Javier; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We demonstrate a technique to mitigate the residual second-order non-local effects in Brillouin optical time-domain analysis (BOTDA) sensors in which the Brillouin frequency shift (BFS) profile is not uniform along the fiber. It is based on adding a wavelength modulation to the probe wave that makes it track the average BFS found along its way. Using this method we are able to inject a total probe wave power of 15 dBm in a 120-km sensing fiber link, which, to the best of our knowledge, is the highest probe power ever demonstrated in a long-range BOTDA sensing fiber link. The enhancement in the detected signal-to-noise ratio brought by the use of such power provides 2-MHz BFS measurement precision at the end of the 120-km sensing link with 3-m spatial resolution, all without the need to resort to additional means such as the use of coding or Raman gain.
Open Access
Zuntz optikoan oinarritutako sentsoreen prestazioen muga-efektu berria, egituren egoera monitorizatzea helburu
(Udako Euskal Unibertsitatea, 2017) Iribas Pardo, Haritz; Mariñelarena Ollacarizqueta, Jon; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Brillouin denbora-eremu optikoaren analisian (BOTDA) oinarritutako sentsoreak estruktura handien (120 km luzerako estrukturak) deformazioa eta tenperatura neurtzeko gaitasuna dute, metro bateko bereizmen espazialarekin. Lan honetan, sentsorearen merkatu-prezioa handitu gabe bereizmen espazial txikiagoa lortzeko beharrezkoa litzatekeen teknika erabiltzeak dituen efektu kaltegarriak aztertu egin dira. Izan ere, pultsu azkar bat sortzeko beharrezkoak diren Mach-Zehnder modulagailu elektrooptikoek iraungitze-ratio (ER) txikia dute. Horiek horrela, aztertu egin da pultsatutako seinalea sortzeko sorgailuak duen ERaren eragina BOTDA sentsoreen prestazioetan, akats handiak sortzen direla ondorioztatuz.
Open Access
Detrimental effects in Brillouin distributed sensors caused by EDFA transient
(Optical Society of America, 2017) Feng, Cheng; Iribas Pardo, Haritz; Mariñelarena Ollacarizqueta, Jon; Schneider, Thomas; Loayssa Lara, Alayn; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We investigate the deleterious effect and the error in Brillouin optical time-domain analyzers induced by the combination of a low extinction ratio pulse generation with the transient behavior of erbium-doped fiber amplifiers.
Open Access
Teacher degree students attitudes towards STEM activities in two spanish universities
(Universidade do Porto, 2022) Lasa Oyarbide, Aitzol; Iribas Pardo, Haritz; Belletich Ruiz, Olga; Wilhelmi, Miguel R.; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Gobierno de Navarra / Nafarroako Gobernua
The attempt to train undergraduate primary school teachers in STEM skills faces an evident handicap, since students enrolling Teacher Degrees usually have humanistic secondary school backgrounds. Attitudes towards STEM on a sample of 336 undergraduate teachers from two Spanish universities were analyzed. Students answered a questionnaire, and responses were analyzed qualitatively (open text questions) and quantitatively (Descriptive Statistics and Statistical Implicative Analysis). Results describe a young collective, with a clear majority of women, mostly interested in languages and history, with high vocation (rather spontaneous than hereditary) to work with children. There is evidence that school advice services fulfill a role to discourage certain students from STEM. These conclusions give valuable information that could be used to replace institutional practices and improve the perception future teachers have towards the teaching of STEM in Primary Education.